Fluid filter assembly with sight glass

ABSTRACT

A fluid filter assembly with sight glass provides an upper housing carrying a transparent sight glass for visualizing the interior of the filter assembly and fluids passing therethrough. A sight glass retainer secures the sight glass within the upper housing. A screen filter is carried between the upper housing and a mating lower housing. A fluid inlet port is defined in the upper housing above the screen filter and a fluid output port is defined in the lower housing below the screen filter. The sight glass retainer carries plural fluid deflectors and plural sight glass supports for fluid dispersion and fluid cooling. A pressurized air input communicating with fluid inlet port allows pressurized air to be injected into the assembly to force fluids through the screen filter and out of the filter assembly. A low pressure drain valve and a bypass valve are carried in the lower housing.

RELATED APPLICATIONS

This application claims the benefit of earlier filed U.S. ProvisionalPatent Application No. 61/518,548 titled FLUID FILTER ASSEMBLY WITHSIGHT GLASS filed on May 9, 2011, and also earlier filed U.S.Provisional Application No. 61/518,213, titled FLUID FILTER ASSEMBLYWITH SIGHT GLASS, filed on May 3, 2011. By this reference, the entirecontents of the aforementioned two Provisional patent applications areincorporated herein.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates generally to filters, and morespecifically to a fluid filter assembly for filtering fluids such asoils, fuels and lubricants.

2. Background of the Invention and Description of the Prior Art

Filters for the removal of particulates and contaminants from fluids areknown. Likewise, filters for filtering oils, fuels and lubricantsdelivered to internal combustion engines, transmissions and othermechanical apparatus are known. The purpose and object of such filtersis to remove dirt, debris and particulates that accumulate duringoperation and also to remove debris “thrown off” the mechanicalcomponents of the apparatus during operation. The filters separate andsegregate the particulates, dirt and debris from the fluid to preventthose items from causing wear and damage to the mechanical apparatus,while permitting the fluids to continually flow through the filter forlubrication and cooling. Although there has been tremendous advancementsin filter technology over the years, two problematic aspects offiltering fluids has remained unresolved, first determining when a fluidfilter has become plugged with dirt, contaminants and particles suchthat the flow of lubricant therethrough is diminished/restricted, andsecond determining what has caused the filter to become plugged. (e.g.dirt from normal usage or particulates that could be indicative of afailing component).

A variety of means and methods to detect when a fluid filter is becomingplugged with contaminants and the like have been developed. Most suchmeans and methods use a change of fluid pressure to warn the user thatthe filter is becoming plugged. The change in fluid pressure may be anincrease in fluid pressure going into the filter, or decrease in fluidpressure coming out of the filter. Other means rely on inspectionwindows or transparent construction of the filter to visualize thecondition of the fluid passing therethrough.

Although sight windows and transparent construction have provided meansto inspect some fluids, many sight windows and transparent constructionmethods have remained ineffective when the fluid to be inspected isopaque, such as engine oil, and modern lubricants that have a variety ofadditives therein. Opaque fluids make it impossible for a user tovisualize contaminants or particles on a filter element without drainingthe fluid from the fluid filter assembly and the mechanical apparatus,which is a significant portion of the work involved with changing thefluid entirely. At least partially because of these continuing problems,most fluid filters are disposable and are replaced when the fluid ischanged without any inspection of the filter element itself forparticulates that may be indicative of a potential mechanical failure.Further, dirty/used fluid filters are classified as hazardous waste andproper disposal thereof is expensive.

Engine failures are commonly a result of bearing failure caused by lackof lubrication and lack of cooling. When lubricant flow ceases, or issignificantly diminished, such as when a oil filter becomes “plugged”the bearings suffer excessive wear and generate excessive heat thatexacerbates the wear and can ultimately lead to mechanical failure ofthe components and catastrophic engine damage. In other instances,mechanical components may fail and the operator will not be aware of theoccurring failure until after a catastrophic event which may costsignificant amounts of money to repair.

My fluid filter with a sight glass overcomes various of these problemsby providing a fluid filter assembly having a first housing carrying atransparent sight glass, a screen filter visible through the sightglass, and a second housing sealed to the first housing and carrying alow pressure drain valve and a bypass valve.

My fluid filter assembly with sight glass is an early warning deviceallowing a user to determine if a problem is developing within amechanical apparatus. In some instances my fluid filter assembly mayallow a user to determine which particular component is the failing. Forinstance, if bearing material, or valve spring material is present onthe filter element, it is indicative of those components failing.

My filter assembly flows fluid through an inlet opening then into pluralradially spaced arcuate openings defined in a sight glass retainer thatfunction as separate filters within the assembly. Each arcuate openingcommunicates fluid onto a portion of a screen filter exposed by eacharcuate opening. The fluid flows through the filter element into matingarcuate recesses defined in a lower housing. The arcuate recesses in thelower housing communicate with plural fluid passages and with an outletpassage. The plural arcuate openings defined in the sight glass retainerhave vertically extending fluid deflectors adjacent edge portions of thearcuate openings which catch dirt, contaminants and particulates, anddistribute the fluid, dirt, contaminants and particles across thesurface of the screen filter. The plural openings function as individualfilters. If the screen filter of one opening becomes plugged the fluidwill still flow through the remaining openings that have not plugged. Inthe event the entire screen filter becomes plugged sufficiently torestrict the flow of fluid through the screen filter, the fluid filterassembly has a bypass valve. The bypass valve will open if the pressureof the fluid rises to a predetermined pressure. When the bypass valveopens it allows fluid to flow therethrough without passing through thescreen filter. Even though the fluid passing through the bypass valve isnot being filtered it will still tend to prevent catastrophic failurecaused by the complete absence of fluid flow.

My fluid filter assembly provides a means to visualize the screen filterelement regardless of the type of fluid being filtered without the needto drain the fluid from the fluid system. My fluid filter assembly alsohas a low pressure drain valve which functions responsive to fluidpressure. When the filter assembly is pressurized, the low pressuredrain valve closes forcing the fluid out through the outlet opening andto the apparatus to which the fluid filter assembly is attached, e.g. aninternal combustion motor. When fluid pressure is removed (e.g. theinternal combustion motor is turned off), the low pressure drain valveopens which allows the fluid to flow out of the filter assembly and intoa fluid reservoir, such as an oil pan. My fluid filter assembly also hasa pressurized air input valve that allows a user to inject pressurizedair into the filter assembly which forces the fluid through the screenfilter, and out through the outlet opening allowing a user to inspectthe screen filter for contaminants and particulates. Pressurized airinput eliminates the need to plumb an additional drain line to drain theassembly and forces viscous fluids through the screen filter leavingparticulates and contaminants visible to a user for identification.

In a second embodiment my fluid filter assembly is modified to carry aremovable disposable fluid filter on a bottom portion of the filterassembly. The addition of a removable disposable filter allows a user tofilter microscopic particles out of a fluid and still allow a user tovisually inspect the fluid and the screen filter for any largerparticles trapped on a screen filter element visible through the sightglass. A water separator may also be installed if a user desires toremove water from the fluid being filtered.

The ability to use a disposable fluid filter is important becausevarious vehicle and equipment warranties may be voided unless a specifictype of disposable fluid filter is used. The second embodiment of myfilter assembly resolves this need for the user who wants to visuallyinspect for particles filtered out of a fluid and remain protected byvehicle or equipment warranties. This fluid filter will also extend theuseful life of a disposable filter.

Some or all of the drawbacks and problems explained above, and otherdrawbacks and problems, may be helped or solved by my invention shownand described herein. My invention may also be used to address otherproblems not set out herein or which become apparent at a later time.The future may also bring to light unknown benefits which may be in thefuture appreciated from the novel invention shown and described herein.

My invention does not reside in any one of the identified featuresindividually, but rather in the synergistic combination of all of itsstructures, which give rise to the functions necessarily flowingtherefrom as hereinafter specified and claimed.

SUMMARY OF THE INVENTION

My fluid filter assembly with sight glass provides a first upper housingcarrying a transparent sight glass for visualizing the interior of thefilter assembly. A sight glass retainer secures the sight glass insidethe first upper housing and communicates with a screen filter carriedbetween the first upper housing and a second lower housing. A fluidinput port is defined in the upper housing and a fluid output port isdefined in the lower housing. The sight glass retainer defines pluralspacedly arrayed fluid deflectors and plural sight glass supports on anupper surface that provide fluid dispersion and fluid cooling. Apressurized air input communicating with the fluid inlet port allowspressurized air to be injected into the assembly to force fluids throughthe screen filter. A low pressure drain valve and a bypass valve arecarried in the lower housing.

In providing such a fluid filter assembly with sight glass it is:

a principal object to provide such a fluid filter assembly that allows auser to visually inspect the filter element and the contaminants andparticulates removed from the fluid without the need of draining,leaking, or the loss of any fluid out of the fluid system and withoutthe need to unbolt or loosen any fasteners, fittings, or hoses.

a further object to provide a fluid filter assembly that does notobstruct or restrict fluid flow when the filter element is plugged withdirt, contaminants and particulates.

a further object to provide such an assembly that is usable with avariety of fluids.

a further object to provide such an assembly that is easy to install andincorporate into a variety of fluid filtering applications and may beremotely mounted.

a further object to provide such an assembly that has multiple fluidinlet ports and fluid outlet ports to accommodate a variety ofapplications and eliminate the need for multiple filters.

a further object to provide such an assembly that withstands high fluidpressures and high flow volumes without restricting fluid flow.

a further object to provide such an assembly that is operable underpositive pressure as well as negative pressure.

a further object to provide such an assembly that uses a replaceablestainless steel wire mesh screen filter element.

a further object to provide such an assembly using a filter element thatis customizable for the size of particle desired to be filtered from thefluid.

a further object to provide such an assembly that allows a user toexamine the particulates and contaminants collected on the filter screento decipher if the particulates and contaminants are from normaloperation or if the particulates and contaminants are evidence offailure of mechanical components.

a further object to provide such an assembly that is an early warningdevice for mechanical failure.

a further object to provide such an assembly having a bypass valveallowing fluids to bypass the screen filter element if the screen filterelement becomes sufficiently plugged to restrict fluid flowtherethrough.

a further object to provide such an assembly having a low-pressure drainvalve that closes when the system is operating and opens when pressureis removed allowing the fluid to drain to a fluid reservoir.

a further object to provide such an assembly having a pressurized airinput port to clear the assembly of fluid for visual inspection of thefilter screen.

a further object to provide such an assembly that allows the screenelement to be removed, cleaned or replaced without the need to drain thefluid system or causing loss of fluid from the system.

a further object to provide such an assembly where it is nearlyimpossible to install a screen filter incorrectly.

a further object to provide such an assembly that is made out ofmaterials that can be recycled and produced out of recycled materials.

a further object to provide such an assembly that eliminates the needfor disposable filters that are hazardous waste.

a further object to provide such an assembly that accepts a disposablefilter cartridge to satisfy manufacturer warranties.

a further object to provide such an assembly that may extend the usefullife of a disposable filter.

Other and further objects of my invention will appear from the followingspecification and accompanying drawings which form a part hereof. Incarrying out the objects of my invention it is to be understood that itsstructures and features and steps are susceptible to change in designand arrangement and order with only one preferred and practicalembodiment of the best known mode being illustrated in the accompanyingdrawings and specified as is required.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific forms, configurations, embodiments and/or diagrams relating toand helping to describe preferred versions of my invention are explainedand characterized herein, often with reference to the accompanyingdrawings. The drawings and all features shown therein also serve as partof the disclosure of my invention, whether described in text or merelyby graphical disclosure alone. Such drawings are briefly describedbelow.

FIG. 1 is an isometric top, side and end view of my fluid filterassembly.

FIG. 2 is an isometric bottom, side and end view the fluid filterassembly of FIG. 1.

FIG. 3 is an exploded isometric view of the fluid filter assembly ofFIG. 1.

FIG. 4 is an isometric top, side and end view of the upper housing.

FIG. 5 is an isometric bottom and end view of the upper housing of FIG.4.

FIG. 6 is an isometric top and end view of the sight glass retainer.

FIG. 7 is an isometric bottom and end view of the sight glass retainerof FIG. 6.

FIG. 8 is an isometric top and end view of the lower housing.

FIG. 9 is an isometric bottom, side and end view of the lower housing.

FIG. 10 is a partial cross-section of the of the lower housing taken online 10-10 of FIG. 2.

FIG. 11 is a cross section view of the filter assembly, taken on line11-11 of FIG. 1.

FIG. 12 is an enlarged view of the sealing elements of the sight glasstaken from FIG. 11.

FIG. 13 is an enlarged view of the sealing elements of the filterelement taken from FIG. 11.

FIG. 14 is an enlarged exploded view of the low pressure drain valveassembly.

FIG. 15 is an isometric bottom, side and end view of second embodimentof the lower housing that releasably accepts a disposable filter, suchas an oil filter or a water separator.

FIG. 16 is an isometric top and side view of a prior art disposablefluid filter of the type that may be releasable attached to the lowerhousing of FIG. 15.

DESCRIPTION OF PREFERRED EMBODIMENT

The readers of this document should understand that the embodimentsdescribed herein may rely on terminology used in any section of thisdocument and other terms readily apparent from the drawings and thelanguage common therefore as may be known in a particular art and suchas known or indicated and provided by dictionaries. Dictionaries wereused in the preparation of this document. Widely known and used in thepreparation hereof are Webster's Third New International Dictionary(©1993), The Oxford English Dictionary (Second Edition, ©1989), The NewCentury Dictionary (©2001-2005) and the American Heritage Dictionary ofthe English Language (4th Edition ©2000) all of which are herebyincorporated by reference for interpretation of terms used herein andfor application and use of words defined in such references to moreadequately or aptly describe various features, aspects and conceptsshown or otherwise described herein using more appropriate words havingmeanings applicable to such features, aspects and concepts.

This document is premised upon using one or more terms or features shownin one embodiment that may also apply to or be combined with otherembodiments for similar structures, functions, features and aspects ofthe invention and provides additional embodiments of the invention.Wording used in the claims is also descriptive of the invention and thetext of both claims and abstract are incorporated by reference into thedescription entirely. Terminology used with one, some or all embodimentsmay be used for describing and defining the technology and exclusiverights associated herewith.

The readers of this document should further understand that theembodiments described herein may rely on terminology and features usedin any section or embodiment shown in this document and other termsreadily apparent from the drawings and language common or propertherefore.

My fluid filter assembly with sight glass 18 provides a first upperhousing 19, a sight glass 50, a sight glass retainer 65, a screen filter95, a bypass valve 190, a low pressure drain valve 157 and a secondlower housing 130.

The first upper housing 19 is preferably machined from a billet ofaluminum, but may be formed from other materials, and is generallycircular in configuration having top 20 and bottom 33. A mounting flange25 extends around circumference of the upper housing 19 and definestherein, a plurality of spacedly arrayed mounting holes 26, 27 forreleasably securing the upper housing 19 to the sight glass retainer 65and to the lower housing 130. The top 20 of the upper housing 19 definessight glass opening 22 with a cross piece 21 extending diametricallyacross the sight glass opening 22. The cross piece 21 prevents the sightglass 50 from “bowing” outwardly when under high pressure which maycause fluid leaks or sight glass fatigue or failure. High pressureapplications may need an extra cross piece 21 which may form a crossbrace across the sight glass opening 22. The thickness of the crosspiece 21 and the sight glass may be adjusted to accommodate extremehigher pressures. At generally diametrically opposed positions, theupper housing 19 carries rectilinear enlargements that extend radiallyfrom the upper housing 19. Each rectilinear enlargement defines aradially aligned threaded fluid inlet port 24 communicating with aninner fluid inlet orifice 23 for flow of fluid into the assembly 18.Inlet ports 24 are threaded to releasably accommodate a known plumbingfitting 44 that defines a medial channel 44 a extending axiallytherethrough communicating with a source of fluid to be filtered (notshown), or alternatively to releasably carry a plug 46, if one inletport 24 is sealed.

As shown in FIG. 4, a pressurized air inlet 38 is defined in one of therectilinear enlargements. The air pressure inlet 38 communicates withthe interior of the assembly 18 for injection of pressurized air thereinto purge fluids therefrom. FIG. 5 also shows air pressure passage 37which is the inside end of the pressurized air inlet 38.

As shown in FIG. 5, the bottom 33 of the upper housing 19 defines sightglass bore 30 to carry the sight glass 50, and an O-ring sealing surface32 that extends radially inwardly from the sight glass bore 30circumferential surface adjacent to the top 20 of the upper housing 19.The circumferential surface of the sight glass bore 30 defines an O-ringgroove 29 to carry an O-ring 180 to provide a fluid tight seal withcircumferential surface of the sight glass 50.

The bottom 33 of the mounting flange 25 defines a recess 28 to carry thesight glass retainer 65. The recess 28 is machined deep enough so thesight glass retainer 65 is co-planar with bottom 33 of the upper housing19. The outer periphery of the recess 28 is similar to the configurationof the mounting flange 25 and also similar to the outer configuration ofthe sight glass retainer 65. (FIG. 6).

The sight glass 50 (FIG. 3) is circular in configuration having a topsurface 58, a bottom surface (not shown) and a circumferential surface52 extending thereabout. In the preferred embodiment, the sight glass 50is formed of a material such as polycarbonate, acrylic, Lexan® or glasssuch as, but not limited to Pyrex® which are transparent, strong, andresistant to heat, chemicals, petroleum and additives frequently carriedin fluids that might be filtered by the assembly 18. The sight glass 50preferably has a scratch resistant and oil and chemical resistantcoating (not shown) which helps keep the sight glass 50 transparent andclear regardless of the type of fluid being filtered. In the preferredembodiment the sight glass 50 is Makrolon® polycarbonate with an ARsurface coating.

An O-ring groove 54 is defined in the top surface 58 of the sight glass50 radially inward to the circumferential surface 52 to carry an O-ring179 therein to provide a fluid tight seal with the upper housing 19.Probably best shown in FIG. 12, the sight glass 50 has a beveled edge 56at the corner where of the outer circumferential surface 52 and the topsurface 58 meet. The beveled edge 56 is useful when inserting the sightglass 50 into the sight glass bore 30 so that the sight glass 50 doesnot “catch on” or damage O-ring 180 carried in O-ring groove 29 definedin the circumferential surface of the sight glass bore 30. The use oftwo O-rings, 179, 180, 181 to seal the sight glass 50 into the upperhousing 19 allows the assembly 18 to withstand high pressures of fluidsbeing filtered therethrough without leaking. The sight glass 50 ispositionally maintained within the sight glass bore 30 of the upperhousing 19 by the sight glass retainer 65.

Sight glass retainer 65 (FIGS. 6 and 7), is preferably machined from abillet of aluminum, but may be formed from other materials, and isgenerally circular in configuration and defines a plurality of spacedlyarrayed mounting holes 77, 78 in a mounting flange 67 extending aroundperiphery of the sight glass retainer 65. The sight glass retainer 65has a top 91 and an opposing bottom 87 and defines a plurality ofspacedly arrayed arcuate openings 70 that communicate from the top 91 tothe bottom 87. The top 91 of the sight glass retainer 65 also carries aplurality of arcuate sight glass supports 72, 74 that are spacedlyarrayed about the top 91 and adjacent to the arcuate openings 70. Thesight glass supports 72, 74 extend vertically perpendicularly from thetop 91 and are preferably generally equally spaced from one another. Thesight glass supports 72, 74 frictionally communicate with a bottomsurface (not shown) of the sight glass 50 and force the sight glass 50into the sight glass bore 30 defined in the upper housing 19 andcompress the O-ring 179 to seal the sight glass 50 into to the upperhousing 19 and provide a fluid tight seal therebetween. The arcuateopenings 70 allow fluids being filtered to pass therethrough forfiltering by the screen filter 95 thereunder.

Fluid deflectors 73 are also carried on the top 91 of the sight glassretainer 65 and are spacedly arrayed thereon about the arcuate openings70. The fluid deflectors 73 disburse the fluid about the sight glassretainer 65 and into a plurality of the arcuate openings 70. Further,the fluid deflectors 73 operate to cool and distribute the fluid beingfiltered and further distribute any particulates and contaminants thatmight be carried within the fluid to the various arcuate openings 70.

Bypass valve feed hole 82 is defined in the center of the sight glassretainer 65 and communicates with the bypass valve 190 carried withinthe lower housing 130.

O-ring groove 80 is defined in the top 91 of the sight glass retainer 65radially outwardly from sight glass supports 72. O-ring 181 is carriedin the O-ring groove 80 to provide a fluid tight seal between the top 91of the sight glass retainer 65 and the recess 28 for the sight glassretainer 65 defined in the bottom 33 of the mounting flange 25 of theupper housing 19.

The bottom 87 (FIG. 7) of the sight glass retainer 65 has the samegeneral configuration as the top 91 but without the fluid deflectors 73and without the sight glass supports 72, 74. An outer seal seat 84 isdefined in the bottom 87 extending about the periphery radially inwardfrom the mounting flange 67. An inner seal seat 85 is defined in thebottom 87 radially outward from the bypass valve feed hole 82. The outerseal seat 84 and the inner seal seat 85 are configured to communicatewith and carry therein inner and outer seals 100, 98, respectively, ofthe screen filter 95. As can be seen in FIG. 7, select mounting holes78, defined in the mounting flange 67 are counter sunk 79 to accommodatehead portions (not shown) of fasteners 90 (FIG. 3) that extend throughthe mounting holes 78 and threadably engage with threaded mounting holes27 defined in the upper housing 19. The countersinking 79 of themounting holes 78 prevents the head portions (not shown) of thefasteners 90 from interfering with the sealing of the upper housing 19with the lower housing 130.

The screen filter 95 (FIG. 3) is circular in configuration and ispreferably comprised of a stainless steel wire screen mesh 97 that isavailable in a variety of sizes capable of filtering macro-particles tomicro-particles.

An outer seal 98 is carried at the outer periphery of the screen filter95 and extends circumferentially thereabout. Similarly, an inner seal100 is carried about circumference of bypass hole 102 defined in acenter portion of the screen filter 95. The inner seal 100 and the outerseal 98 have similar configurations and, as shown in FIG. 13, the outerseal 98 is compressed into the outer seal seat 84 defined in the bottom87 of the sight glass retainer 65 and in the outer seal seat 138 definedin a top 132 of the lower housing 130.

The assembled upper portion of the assembly 18, which compromises theupper housing 19, the sight glass 50 and the sight glass retainer 65need not be disassembled for any reason other than the replacement ofthe O-rings 179, 180, if necessary.

The second lower housing 130 (FIGS. 8, 9, and 10) is preferably machinedfrom a billet of aluminum, but may be formed from other materials, andhas a top 132, an opposing bottom 172, and has an outlet channel housing174 carried on the bottom 172 extending diametrically there across.

The top 132 of the lower housing 130 is similar in configuration to thebottom 87 of the sight glass retainer 65 and is complementary thereto.The top 132 defines plural arcuate recesses 146 that align with theplural arcuate openings 70 defined in the sight glass retainer 65. Eachof the arcuate recesses 146 defines a fluid passage 148 thatcommunicates with an outlet passage 150 defined in the outlet channelhousing 174. The outlet passage 150 extends diametrically across thelower housing 130 and defines a fluid outlet port 144 at each endportion. Each fluid outlet port 144 is threaded to releasably engagewith a known plumbing fitting 45, defines a medial channel 45 aextending axially therethrough, or a known plug 46 (FIG. 10) if thefluid outlet port 144 is to be sealed.

Drain valve pressure passage 141 (FIG. 8) is defined in at least one ofthe arcuate recesses 146. The drain valve pressure passage 141communicates with the low-pressure drain valve 157.

Outer seal seat 138 and inner seal seat 139 are defined in the top 132of the lower housing 130 at positions to receive the inner seal 100 andouter seal 98 of the screen filter 95.

Mounting flange 133 extends around the periphery of the lower housing130 and defines four spacedly arrayed mounting holes 135 for threadedfasteners 35 and washers 36 to releasably secure the lower housing 130to the upper housing 19. The fasteners 35 pass through the upper housing19 mounting holes 26 and through the mounting holes 77 defined in thesight window retainer 65 and thereafter engage with the threadedmounting holes 135 defined in the lower housing 130. As can be seen inFIGS. 1 and 2, it may be necessary to form of a slight concavedepression in the outer circumferential surface of the upper housing 19radially adjacent each mounting hole 26 to accommodate the head portionof the fastener 35 and the washer 36.

As shown in FIG. 11, when the assembled upper housing 19 is secured tothe lower housing 130 by the plural fasteners 35, the outer seal 98 andinner seal 100 of the screen filter 95 are compressed in the alignedouter seal seats 84, 138 and the aligned inner seals seats 85, 139 toprovide a fluid tight seal between the upper housing 19, the sight glassretainer 65, the screen filter 95 and the lower housing 130 that willnot leak even when exposed to high working pressures up to approximately350 psi. The compression of the seals 98, 100 forces any fluid enteringthe assembly through fluid inlet ports 24 to pass through the screenfilter 95 in order to exit the assembly 18 through the fluid outletports 144.

FIG. 2 shows a bottom view of the assembled fluid filter assembly 18having four spacedly arrayed threaded mounting holes 170. Three of themounting holes 170 are machined and into a bottom surface 176 of theoutlet passage housing 174 while a fourth mounting hole 170 is definedin an end portion of a mounting boss 171 so that all of the mountingholes 170 are at the same vertical level allowing the assembly 18 to bemounted in a variety of orientations to accommodate a variety oflocations and applications. In the preferred embodiment, the assembly 18is mounted horizontally with the sight glass 50 facing upwardly. It isanticipated that only two of the mounting holes 170 are necessarilyrequired to mount the assembly 18 for use.

The outlet passage housing 174 contains the low-pressure drain valveassembly 151 (FIGS. 14, 10). The low-pressure drain valve assembly 151generally comprises drain valve channel 155 defined in the outletpassage housing 174, drain valve 157, drain valve spring 158 and aretainer fitting 159. (FIG. 14).

The drain valve 157 has a drain valve spring seat 153 at one end portionand a beveled sealing seat 152 at an opposing end portion to form afluid tight seal with the retainer fitting 159. The drain valve spring158 has a first end portion that fictionally communicates with thespring seat 153 and a second end portion that frictionally communicateswith a spring seat 154 at an end portion of the retainer fitting 159. Asshown in FIG. 14, the retainer fitting 159 defines a medial channel 159a extending axially therethrough so that fluid may pass therethrough.

The drain valve spring 158 biases the drain valve 157 to a positionwithin the drain valve channel 155 so that the drain passage 161 is notobstructed and fluid may pass therethrough and into medial channel 159 aof the retainer fitting 159 to exit the assembly 18 to a fluid reservoirsuch as an oil pan. (Not shown). It is preferable that the valve spring158 carry approximately 10 pounds per square inch (10 psi) of pressureto positionally maintain the drain valve 157 against a drain valve seat(not shown) within the drain valve channel 155 when there is no fluidpressure within the assembly 18. For example, when an internalcombustion motor (not shown) to which the assembly 18 is attached is“turned off” the fluid pressure will drop to zero and the valve spring158 would have sufficient strength to move the drain valve 157 to abiased position within the drain valve channel 155 allowing the drainpassage 161 to open and remain unobstructed.

As shown in FIG. 10, when the drain valve 157 is positioned against asealing seat (not shown) within the drain valve channel 155, fluid mayfreely pass from the outlet passage 150 through fluid drain passage 161,and thereafter to fluid reservoir (not shown). Outer opening of thedrain passage 161 opposite the outlet passage 150 is preferably sealedwith a threaded plug 162 which forces the fluid to pass through themedial channel 159 a defined in the retainer fitting 159. After thefluid passes through the retainer fitting medial channel 159 a, thefluid may flow back to a fluid reservoir (not shown).

As shown in FIG. 10, pressure port passage 164 is defined in the outletpassage housing 174 and transects the drain valve pressure passage 141and communicates with the outlet passage 150. The pressure port passage164 is threaded at its outer opening (FIG. 9) to receive a threaded plug163. If necessary, the pressure port passage 164 may be interconnectedwith a known pressure valve (not shown), or other known device todetermine fluid pressures within the assembly 18. The pressure portpassage 164 and the drain valve pressure passage 141 both supply fluidpressure to an end portion of the drain valve 157 opposite the drainvalve spring 158. When the assembly 18 is pressurized, such as when aninternal combustion motor is started, fluid pressure passing through thedrain valve pressure passage 141 and the pressure port passage 164 exertpressure on the drain valve 157 causing it to move axially within thedrain valve channel 155 compressing the drain valve spring 158 andovercoming the spring biasing. The movement of the drain valve 157 andcompression of the spring 158 causes the sealing seat 152 tofrictionally engage with the valve seat 156 of the retainer fitting 159which seals the fluid drain port 161 and prevents fluid from flowingthrough the low pressure drain valve 157.

The low-pressure drain valve assembly 151 allows the assembly 18 todrain of fluids when not under pressure. The low pressure drain valveassembly 151 only closes when pressure exists inside the assembly.Because the draining action of the low pressure drain valve assembly 151is gravitational, those familiar in the art will readily recognize thatthe assembly 18 must be positioned vertically above the fluid reservoirinto which the fluid will flow.

As shown in FIG. 3, a one-way air valve housing 40 is threadably carriedwithin the pressured air inlet 38 defined in the upper housing 19. Theair valve housing 40 defines a threaded medial channel extendingtherethrough (not shown) and carries within the medial channel (notshown) an air valve 39 so that pressurized air may be injected into theassembly 18 below the sight glass 50 and above the screen filter 95. Theinjection of pressurized air into the assembly 18 forces the fluidsthrough the screen filter 95 and through the fluid outlet ports 144defined in the lower housing 130. Forcing the fluids through the screenfilter 95 will leave any particulates, contaminants and the like thatare larger than the screen openings (not shown) captured on the screenfilter 95 so that the particulates and contaminants may be viewed by auser examining the screen filter 95 through the sight glass 50.

The input air valve 39 is a one-way valve so fluid, and pressure cannotleak therethrough in the opposite direction. The air valve housing 40and air valve 39 are similar in construction to an air valve carried onan automobile tire and as such, standard air valve fittings, may be usedto supply pressurized air to the assembly 18. The air valve 39 isparticularly important if chemical additives (not shown) have been addedto the fluid being filtered which may cause viscosity to increase andcause the fluid to “gum up” on the screen filter 95 and impede draining.Addition of air pressure to the assembly 18 “a head of” the screenfilter 95 forces such high viscosity fluids through the screen filter 95to reveal the particulates and contaminants captured on/by the screenfilter 95.

As shown in FIG. 11, the bypass valve 190 is carried within the lowerhousing 130 and is comprised of a stainless steel ball 165 thatfunctions as the valve, a bypass valve spring 166 that exerts continuouspressure on the steel ball 165 and a bypass valve spring seat plug 167that threadably engages in a threaded bypass valve hole 168 defined inthe outlet passage housing 174. (FIG. 9). The steel ball 165 “seats” ina bypass valve seat 175 machined into the lower housing 130. The bypassvalve seat 175 is diametrically smaller than the diameter of the steelball 165 so that pressure exerted by the bypass valve spring 166 forcesthe steel ball 165 against the bypass valve seat 175 to prevent fluidsfrom flowing therebetween.

The bypass valve spring 166 transects the outlet channel 150 defined inthe outlet passage housing 174. The strength of the bypass valve spring166 may be altered by changing the spring 166 as desired by a user toexert more or less pressure on the steel ball 165 which responsivelyadjusts the amount of pressure that must exist within the assembly 18and above the screen filter 95 before the pressure within the assembly18 above the screen filter 95 is sufficient to force the ball bearing165 away from the bypass valve seat 175 to allow the fluid to passtherebetween through the bypass passage 143, rather than forcing thefluid to pass through the screen filter 95.

The bypass valve 190 is a safety feature for the assembly 18 and is onlyactuated when the screen filter 95 becomes sufficiently plugged to nolonger allow sufficient fluid to pass through the screen filter 95. Whenthat event occurs, the pressure within the assembly 18 in the volumebetween the sight glass 50 and the screen filter 95 will rise to asufficient level to force the steel ball 165 away from the bypass valveseat 175 so that the fluid may pass from above the screen filter 95 anddirectly into the outlet passage 150 without being filtered. Althoughthe passage of fluid through the bypass valve 190 allows contaminatedand dirty fluids to pass through the assembly 18, the allowance of thefluid to continue flowing is more likely to prevent a catastrophicfailure that would be caused by a complete absence of fluid forlubrication.

The pressure exerted by the bypass valve spring 166 is known as “seatpressure” and is preferably approximately ten percent (10%) higher thanthe normal operating pressure of the fluid to be filtered by theassembly 18. When the fluid pressure above the screen filter 95 exceedsthe seat pressure by approximately ten percent (10%) causing a pressuredifferential within the filter assembly 18 between above the screenfilter 95 and below the screen filter 95, the pressure differential willforce the steel ball 165 downwardly away from the bypass valve seat 175by compressing the bypass valve spring 166 allowing the fluid to flowaround and about the steel ball 165 rather than forcing the fluid topass through the filter screen 95.

In a second embodiment, as shown in FIG. 15, the lower housing 195 ismodified to releasably carry a disposable filter 210 such as adisposable oil filter, a disposable water filter, a disposable waterseparator, a disposable fuel filter and the like. The second embodimentlower housing 195 has a top surface (not shown) that is identical to thetop 132 of the lower housing 130 shown in FIG. 8. The bottom of thesecond embodiment of the lower housing 195 is configured so a disposablefluid filter 210 or water separator may be threadably engaged thereto ona threaded nipple 197. The threaded nipple 197 is carried by a threadednipple housing 199 and defines a feed channel 198 extendingtherethrough. The feed channel 198 communicates with the outlet passage150 and at least one fluid outlet port 144. A seal receiving groove 202is defined in the housing 195 radially spaced apart from the threadednipple 197 to carry and engage with a rubber seal 213 of the disposablefilter 210. In this second embodiment, fluid passes into the upperhousing 19 through the screen filter 95, then into at least one fluidchannel 146 defined in the lower housing 130, which communicates withplural arcuate openings 70 defined at the sight glass retainer 65. Thefluid then flows into the disposable filter 210 inlet openings 212.After passing through internal filter elements (not shown) of thedisposable fluid cartridge 210, the fluid flows outwardly through fluidoutlet 215 which communicates with feed channel 198 defined by threadednipple 197. The fluid then passes back into the lower housing 195through the outlet passage 150 and though the at least one fluid outletport 144.

Lower housing 195 of the second embodiment defines a pressure portpassage 191 which is threaded at its outer opening to receive a threadedplug 163. If desired, the pressure port passage 191 may beinterconnected with a known pressure valve (not shown), or other knowndevice to determined fluid pressures within the assembly.

Having described the structure of my fluid filter with sight glass itsoperation may be understood.

The assembly 18 is plumbed into the fluidic system (preferably alubrication system, of an apparatus such as an internal combustionengine) in a manner known to those familiar with the art generally bymounting the assembly at a desirable location with fasteners (not shown)that interconnect with the mounting holes 170 defined in the lowerhousing 130.

A first fluid plumbing line, such as a pressurized oil feed line/hose(not shown) is interconnected to at least one of the fluid inlet portfittings 44 to feed dirty fluid into the assembly 18. Similarly, asecond fluid plumbing line (not shown) is interconnected to at least oneof the fluid outlet port fittings 45 to supply filtered fluid back tothe internal combustion engine.

Fluid enters the assembly 18 through the fluid inlet ports 24 and flowsaround and about the fluid deflectors 73 and the sight glass supports72/74 and then into the arcuate openings 70 defined in the sight glassretainer 65. The fluid flows through the screen filter 95 and into thearcuate recesses 146 defined in the lower housing 130. After the fluidpasses into the arcuate recesses 146, the fluid passes thorough thefluid passages 148 and into the outlet passage 150 for passage throughthe at least one outlet port 144 and back to the internal combustionengine.

The above description of my invention has set out various features,functions, methods and other aspects of the invention. This has beendone with regard to the currently preferred embodiments thereof. Timeand further development may change the manner in which the variousaspects are implemented. Such aspects may further be added to by thelanguage of the claims which are incorporated by reference hereinto asoriginally filed. The scope of protection accorded the invention, asdefined by the claims, is not intended to be necessarily limited to thespecific sizes, shapes, features or other aspects of the currentlypreferred embodiment shown and described. The claimed invention may beimplemented or embodied in other forms still being within the conceptsshown, described and claimed herein. Also included are equivalents ofthe invention which can be made without departing from the scope orconcepts properly protected hereby.

The foregoing description of my invention is necessarily of a detailednature so that a specific embodiment of a best mode may be set forth asis required, but it is to be understood that various modifications ofdetails, sizes, and rearrangement, substitution and multiplication ofthe parts may be resorted to without departing from its spirit, essenceor scope.

1. A fluid filter assembly comprising in combination: a first housinghaving a top and a bottom and defining at least one sight glass openingin the top communicating with a sight glass bore and at least one fluidinlet port communicating between an outer surface of the first housingand the sight glass bore; a transparent sight glass carried within thesight glass bore for providing user visibility into interior of thefirst housing; a second housing having a top and a bottom and definingan outlet passage communicating with the top and at least one fluidoutput port communicating between an outer surface of the second housingand the outlet passage, the top of the second housing releasablyattached to the bottom of the first housing in fluid tight engagement;and a screen filter carried between the first housing and the secondhousing and visible through the at least one sight glass opening and thesight glass.
 2. The fluid filter assembly of claim 1 further comprising:a sight glass retainer carried within the first housing to positionallysecure the sight glass within the sight glass bore.
 3. The fluid filterassembly of claim 2 wherein: the sight glass retainer has, a top and abottom, defines plural spaced apart openings communicating between thetop and the bottom, a fluid deflector spacedly adjacent the pluralspaced apart openings to disperse the fluids across the filter screen;and a sight glass support extending upwardly perpendicularly from thetop to frictionally engage with a bottom surface of the sight glass tocompress a sealing means between the sight glass and a surface of thefirst housing to provide a fluid tight seal therebetween.
 4. The fluidfilter assembly of claim 3 wherein: the second housing defines pluralrecesses that align with the plural openings defined in the sight glassretainer to receive fluid passing therethrough; and each recess definesa fluid passage communicating with the outlet passage defined in thelower housing and communicating with the at least one fluid outlet port.5. The fluid filter assembly of claim 1 further comprising: a lowpressure drain valve carried within a drain valve channel defined in thefluid filter assembly, the drain valve channel communicating between theoutlet passage and the outer surface of the fluid filter assembly; abiasing means to positionally bias the low pressure drain valve to anopen position within the drain valve channel to drain fluid from theassembly to a fluid reservoir when fluid pressure is removed from theoutlet passage; and the biasing means is overcome when fluid pressureexists in the outlet passage causing the low pressure drain valve tomove within the drain valve channel to seal against a drain valve seatand retain fluid within the filter assembly while fluid pressureremains.
 6. The fluid filter assembly of claim 1 further comprising: abypass valve communicating between interior of the fluid filter assemblyspacedly adjacent the at least one fluid input port and interior of thefluid filter assembly spaced adjacent the at least one fluid output portto allow fluid to pass therebetween without passing through the screenfilter.
 7. The fluid filter assembly of claim 6 wherein: the bypassvalve has a ball carried in a bypass valve seat communicating between afirst side of the screen filter and a second side of the screen filterto pass fluids therebetween without the fluid passing through the screenfilter; and a biasing means biasing the ball into the bypass valve seatwhich may be overcome to move the ball away from the bypass valve seatwhen fluid pressure within the fluid filter assembly exceeds apredetermined pressure.
 8. The fluid filter assembly of claim 1 furthercomprising: a pressurized air inlet communicating with interior of thefluid filter assembly on one side of the screen filter for supplyingpressurized air to the interior of the assembly to force fluids thoughthe screen filter to cause contaminants on the screen filter to bevisible through the sight glass.
 9. The fluid filter assembly of claim 1wherein: the sight glass provides a means for a user to visually inspectthe filter screen for contaminants and particulates collected on thefilter screen to determine if the contaminants and particulates are fromnormal usage or evidence of an ongoing mechanical failure without theneed to drain the fluid or remove the fluid filter assembly.
 10. Thefluid filter assembly of claim 1 wherein: the screen filter element mayhave a variety of mesh sizes.
 11. The fluid filter assembly of claim 1wherein: the bottom of the second housing is configured to releasablycarry a filter cartridge, the bottom of the second housing, defining atleast one fluid channel communicating between the top and the bottom forcommunicating with at least one fluid inlet opening defined in thefilter cartridge, having a threaded nipple housing carrying a threadednipple to releasably engage with the fluid filter cartridge, thethreaded nipple defining a feed channel fluidically communicating withthe outlet passage and the at least one fluid outlet port.
 12. The fluidfilter assembly of claim 11 wherein: the fluid filter cartridge is anoil filter.
 13. The fluid filter assembly of claim 11 wherein: the fluidfilter cartridge is a water separator filter.
 14. The fluid filterassembly of claim 11 wherein: the fluid filter cartridge is a fuelfilter.
 15. The fluid filter assembly of claim 11 wherein: the bottom ofthe second housing defines a circular seal receiving groove spacedradially outwardly from the threaded nipple to engage with and carry aseal of the disposable filter cartridge to prevent the filter cartridgeseal from failing under high fluid pressure.